Hugh Jackman has played Wolverine in six different movies. While he's still enjoying it, The Wolverine and X-Men: Days of Future Past are sounding like the end. He told EW, "I wasn’t even sure after the first film if I would do another. I won’t say never, because I’m still loving it. But there would have to be a pretty compelling reason."
Jackman could always change his mind, or be replaced. But, that'd be tough. To us, Jackman is Wolverine. Let's just hope X-Men isn't rebooted like Superman and Spiderman have been. I don't think anyone else could really pull off the character - at least not for a few decades and for a whole new generation of movie goers, if ever.